As the use of cellular phones by mobile subscribers is getting more and more profitable to Mobile Network Operators (MNO), there is a growing motivation to limit the use of cellular phone subscribers to a single MNO network.
Existing techniques for limiting the use of mobile subscribers to a single MNO network include configuring a cellular phone with a phone locking mechanism to enable the use of the cell phone only if a compatible SIM (Subscriber Identity Module) card is installed in the cell phone. A SIM card is a smart-card-type device securely storing a private key for identifying a mobile subscriber. The SIM card also includes storage space for storing text messages and telephone numbers.
Many cellular phones used today feature a memory card slot for interfacing with a memory card. A memory card plugged into this slot is a non-volatile memory, typically a flash-based removable memory storage card, which provides the phone with additional storage capacity, typically 16 Mbyte to 1 Gbyte. The additional memory can be used for storing preloaded data and applications, such as pictures, music and games, all of which are supported by the cellular phone's different functionalities.
The memory card is typically sold as an optional accessory and can be purchased from any compatible memory card manufacturer.
A Mobile Network Operator (MNO) may provide a mobile phone to its subscribers at no cost or at a very low cost. The MNO typically limits the use of such a mobile phone by restricting its use to a single MNO network or to the specific subscriber.
Existing techniques for limiting the use of such a mobile phone are typically achieved by implementing a SIM lock mechanism that enables usage of a mobile phone only when the mobile phone is installed with a compatible SIM card that is provided by the MNO together with the mobile phone.
However in situations where service providers may cover the cost of the memory card and also provide the card with preloaded data and applications in order to motivate usage of cellular phone subscribers to their own MNO network, it is highly desirable to limit usage of memory cards to a single MNO network.